Better error message for anonymous class declarations

Author: rattrayalex

src/parser/statement.js

@@ -906,7 +906,7 @@ pp.parseClassId = function (node, isStatement, optionalId) {
     if (optionalId || !isStatement) {
       node.id = null;
     } else {
-      this.unexpected();
+      this.unexpected(null, "A class name is required");
     }
   }
 };

test/fixtures/es2015/uncategorised/263/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token (1:6)"
-}
+  "throws": "A class name is required (1:6)"
+}

test/fixtures/esprima/invalid-syntax/migrated_0261/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token (1:5)"
-}
+  "throws": "A class name is required (1:5)"
+}

test/fixtures/esprima/invalid-syntax/migrated_0262/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token (1:5)"
-}
+  "throws": "A class name is required (1:5)"
+}

test/fixtures/esprima/invalid-syntax/migrated_0263/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "Unexpected token (1:5)"
-}
+  "throws": "A class name is required (1:5)"
+}